1. Field of the Invention
This invention relates to scanning systems used in procedures performed in real-time PCR or on microarrays of biological species such as nucleic acids or proteins, and for any type of procedure or analysis where very rapid illumination, observation, and/or detection are performed at a large number of individual sites arranged in a regular two-dimensional array.
2. Description of the Prior Art
Scanning systems to which this invention is addressed are mechanical conveyances that move a scanning head back and forth at a very rapid rate in a scanning pattern which consists of a line or a series of lines. Scanning systems have been designed for a variety of scanning heads, including those that emit or receive, or both emit and receive, light or other electromagnetic waves or particles, or acoustic signals. Data retrieved during the scan is typically sent to a signal processor for storage, recordation, comparison, and other common signal processing functions.
Targets that can be scanned by scanning systems include radiographic images, electronic packages and other electronic media, and multi-well plates containing arrays of biological samples. In all cases, the goals in effective scanning are high speed and positional accuracy. These goals tend to conflict with each other, however, since the movement of the scanning head requires rapid reversals in direction and rapid back and forth acceleration following the reversals. These accelerations and reversals create undesirable vibrations in the system, which give rise to measurement error and subject the system components to mechanical stresses that can lead to distortion and wear. These and other problems associated with scanning systems are disclosed in Ciechanski, F. J. (Sonoscan, Inc.), U.S. Pat. No. 4,781,067, issued Nov. 1, 1988; Kerr, R. S., et al. (Eastman Kodak Company), U. S. patent application Publication No. US 2005/0133749 A1, published Jun. 23, 2005; Kellerman, P. L., et al., U. S. patent application Publication No. US 2005/0254932 A1, published Nov. 17, 2005; Melville, C. D. (University of Washington), U.S. Pat. No. 5,995,264, issued Nov. 30, 1999; and Chubb, C. F. (Dynell Electronics Corp.), U.S. Pat. No. 3,541,561, issued Nov. 17 1970. The contents of these patents are hereby incorporated herein in their entirety.